diff --git a/common.mk b/common.mk
index 1a1407a..be0b21e 100644
--- a/common.mk
+++ b/common.mk
@@ -63,7 +63,7 @@ endif
 verilog: $(verilog)
 
 romgen := $(BUILD_DIR)/$(CONFIG_PROJECT).$(CONFIG).rom.v
-$(romgen): $(verilog)
+$(romgen): $(verilog) $(BOOTROM_DIR)
 ifneq ($(BOOTROM_DIR),"")
 	$(MAKE) -C $(BOOTROM_DIR) romgen
 	mv $(BUILD_DIR)/rom.v $@